Apparatus for and method of producing high-frequency currents of electricity.



D. G. McCAA. APPARATUS FOR AND METHOD OF PRODUCING HIGH FREQUENCY CURRENTS 0F ELECTRICITY.

APPLICATION FILED SEPT. 24. I913.

Patented Jan. 9, 1917.

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UNITED STATES PATENT OFFICE.-

DAVID G. MCCAA, OF LANCASTER, PENNSYLVANIA.

APPARATUS FOR AND METHOD OF PRODUCING HIGH-FREQUENCY CURRENTS 0F ELECTRICITY.

Application filed September 24, 1913.

To (ZZZ whom it may concern:

Be it 'known that I, DAWI) G. MCCAA, a citizen of the l nited States, residing at 676 \Vest \Valnut street, Lancaster, in the county of Lancaster and State of Pennsyl' vauia, have invented certain new and useful Improvements in Apparatus for and Methods of Producing lligh-Frequency urrents of Electricity. of which the following is a specification.

My present invention, while broadly relating to the general class which comprises devices designed for use in connection with electric signaling systems, has yet more particular relation to that peculiar branch of said class, which comprises devices espe cially designed, both for the production and for the transmission of continuous-high frequency currents of electricity, and such invention contemplates, among other ends, the provision of means whereby a current of electricity of low potential and of alternating character, is converted into a current of high frequency oscillations, of high potential, for use in radiotelegraphy and radiotelephony.

The invention further contemplates the provision of means wherebyarcing of a current of electricity, of the character set forth above, across a spark gap, which is included in the circuit of said current, may be. absolutely prevented.

To the attainment of the ends above outlined, the invention consists in the combination, arrangement and operation of the 1 several parts comprised therein, substantially in the manner hereinafter described and illustrated in the accompanying drawings, wherein:

Figure 1, illustrates in a diagrammatic view, a signal transmitting electric circuit comprising in a. single operating system a current generating circuit, a current converting circuit and a current transmitting circuit each thereof including its appropriate generating, converting or. transmitting devices arranged in accordance with my invention. Fig. 2, illustrates in a diagrammatic view, the wave form of the sin usoidal alternating current of electricity T preferably employ in the present embodiment of my invention. Fig. 3 illustrates, in a diagrammatic view, the character of the UNlllHflOllS produced in both the pri- Specification of Letters Patent.

Patented Jan. 9, 1917.

Serial No. 791,547.

mary and the secondary of the air core transformer, and the relation of such oscillations, each to the other. Fig. 4, illustrates in a detail diagrammatic view, a current Wave, of the type illustrated in Fig. 2, and the relation of such wave to the oscillations set up thereby in the primary employed in the converting circuit of the present embodiment of my invention. Fig.. 5, illustrates an ordinary closed oscillatory circuit including a source of 'supply, a condenser in shunt with such source of supply, a single ball gap and the primary of an air core transformer which latter is connected to impart current to a secondary not shown herein. Fig. (3, illustrates a closed circuit including a source of supply, a condenser and a multiple gap in series with each other, and the primary of an air core transformer.

As has been hereinbefore set forth, the present invention contemplates the conversion of a current of electricity of ordinary low potential and alternating character, that is to say,of low electromotive force and alternating wave flow,into a current of continuous high frequency oscillations, to the end that such current may be successfully employed in the transmission of signals radiotelegraphy and of spoken speechradiotelephony,between stations located at a distance, often very great, from each other, without the employment of conductors of electricity, of any material, or type whatsoever, other than the natural media.

To the attainment of the ends outlined above, various inventions have been heretofore made, each thereof having for its end or'purpose, the avoidance, or the overcoming of some natural, or artificial obstacle, or bar to the attainment of the ends sought thereby, a fact that is equally true of the invention which forms the subject of the present application, as has been indirectly set forth by the statements hereinbefore made, in view of which latter namedfact, it has been thought best, when hereinafter describing my invention, to compare parts thereof with analogous parts of well known devices which have for their purpose the attainment of ends approximating those sought to be attained by the parts of my invention so compared, in order to clearly ascertainthe difference existing therebetween, as well as to more fully determine and set forth the peculiar action of the several parts, or ele ments comprised in my said invention, in comparison with the other devices noted.

Referring to the drawings which form a part hereof and wherein similar letters and numerals of reference denote similar parts, A, designates that portion of my invention which, for the purposes of the present invention, may be termed the current generating circuit, B, designates that portion which may be termed the current converting circuit and G, designates that portion which may be termed the transmitting, or sonorous circuit.

Of the circuits noted, that first named, A, includes an alternator D, which for the purposes of the present invention is preferably of the single phase type, primary 1, of the transformer E, and conductors 2 and 3, through which said primary receives energy from the alternatorand one of which 2, is provided with a key 4, wherewith to close circuit through said generating circuit.

The current converting circuit B, includes the secondary 5, of the transformer E, the

condensers F and G, spark gap H, primary 6, of the air core transformer I and the conductors 7, which electrically connect the several parts last above noted, and the transmitting, or sonorous circuit includes the secondary 8, of the air core transformer I, the antenna J, and interrupter J,which latter named, for the purposes of the present invention, may be placed in the continuation of said secondary as shown, see Fig. 1.

Having thus briefly set forth the general arrangement of the several elements comprised in my invention, I will now proceed to more specifically describe the peculiar nature of such of said elements as go to make up the operativeportion of my invention, as distinguished from the current transmitting portion thereof, that is to say, the conducting wires, and the operation of each of said operative elements so far as re gards each other.

As has been hereinbefore stated, I preferably employ, for the purposes of the present adaptation of my invention, an alternator D, of the single phase variety or type, that-is to say,-an alternator having a single winding upon its armature and adapted to deliver an alternating current of electricity to a single circuit,but while so naming such type of alternator as my preference for use in the present adaptation of my invention, I yet do not desire to limit, or confine myself solely to the same, but instead thereof, I may employ polyphase alternators, that is to 'sayalternators having two or more windings upon their armatures, each of which windings is distinct from the other and each of which delivers muses a distinct current of electricity over a circuit peculiar to itself.

As above stated the type or variety of alternator Which I prefer to employ in the present embodiment of my invention, is that of the single phase and of said type or variety, that particular one which has its armature so wound as to produce a sinusoidal alternating wave current approximately rectangular in outline upon the opposite sides of its neutral or time axis 9, as is indicated at 10 and 11, in Fig. 2, whereby, as will be readily understood. the spa -e between the discharges which occur in pro imity to the zero point, in each alternation of the current wave, is materially shortened and made to accord with those discharges which occur While the electro-motive force of the current wave, is rising to, remaining at and falling from its maximum between the pauses noted, as illustrated in Fig. l.

It is to be understood that Fig 4, last above referred to, is merely illustrative of the pauses, or gaps which occur between the discharges, during the full flow of the current wave on each side of its neutral or time axis 9, and of the time period during which such Wave is moving toward and from its zero of potential, at each alternation of such current, and in no way seeks to illustrate the time period of such discharges, as regards each other and the current \vave flow in which they occur, for, as a matter of fact, a very great number of such discharges may occur during the flow of the wave current in one direction, and be repeated during the next succeeding wave flow in opposite direction.

In connection with the single phase type, or variety of alternator D, hereinbefore noted, I employ a single transformer E, which for the purposes of the present embodiment of my invention, is preferably of the step up type, or variety, that is to say,a transformer wherein the primary coil has a less number of windings, or turns, than the secondary coil, whereby a large current of low electromotive force, received from a generator by the primary of said transformer, is changed or transformed and delivered from the secondary of said transformer, as a small current of high electromotive force,and in the circuit which includes such alternator D, and transformer E, I insert a key 4, whereby to .control current through said circuit.

From the foregoing it will be understood that a large current of low electro-motive force is supplied by the generator D, that such current is, by the transformer E, changed into a small current-of high electromotive force for the energization of the cirof the current supplied by the secondary 5,

is like unto that supplied by the generator D, and that, since a current of both high potential and high frequency is necessary to. the successful operation of the arts noted hereinbefore, to wit, radiotelegraphy and radiotelephony, the frequency of the current supplied by the secondary 5, must be raised to meet the requirements of such arts.

To the end noted I provide the converting circuit B, (which circuit includes both the secondary 5, of the transformer E, and the primary 6, of the transformer 1,) with a plurality of condensers F and G, and a multiple spark gap H,so arranging the parts noted, with relation to each other that one of said condensers, to wit, condenser F, shall be in shunt with the secondary 5, (which, it is to be remembered, is the source of supply of the circuit B,) while the remaining condenser G, is included in the direct circuit between said secondary 5, and the primary 6, of the transformer I, as is also the multiple spark gap H, with which the condenser G, is in series, as shown in Fig. 1, which see.

Having thus outlined the arrangement of the several devices included in the circuit B,

and before going into a detail description of the peculiar cooperation of such devices when connected in the manner. set forth in said circuit, as shown in Fig. 1, I will, as briefly as possible, describe the operation of each of such devices when one or more thereof, (but not the full number shown in Fig. 1,) is included in a circuit similar to that of the converting circuit B, one each of which circuits is shown in each of the Figs. 5 and 6.

Of thefigures noted, the first named Fig.

I 5, illustrates an ordinary high frequency oscillatory circuit, which includes the sec ondary 5, of a step up transformer, a spark gap H,here shown as the ordinary single gap, for purposes of comparison with the multiple gap employed in my -inven tion,the primary 6, of an air core transformer and a condenser F,here shown in shunt with the secondary 5, which latter is the source of supply of said circuit.

As has been hereinbefore stated, the current supplied by the secondary 5, is of high potential and alternating character and this current charges the condenser F, until the potential thereof is raised to a strength sufficient to break down the dielectric resistance of the spark gap H, at which time a discharge across such gap will occur, such discharge appearing as a single spark dur ing the existence of which the condenser will continue to dischargeor in other words to oscillate,until the energy of its decreasing potential is overcome by the increasing dielectric resistance of the gap H, at which time discharge fromthe condenser will cease, until the condenser has'again been charged to repeat the action last above set rent,by decreasing the capacity of the 0011- densers,by shortening the spark gap. It is also to be understood that the time interval between successive discharges is not of like duration, but instead thereof is very irregular, a condition that is due to, and caused by the variation of the dielectric spark resistance of the gap, due to ionization which occurs at the opposite poles of said gap H, during the preceding discharge.

During the action of the oscillatory circuit illustrated in Fig. 5, as last above described it will be understood that the current supplied by the secondary 5, to condenser F, will pass thence to gap H, primary 6 and be returned to condenser F, and further that the discharges noted could be produced at a very high rate of speed per second were it not for the irregular movement of the spark across the gap H, in conjunction with another objectionable feature, to wit, the liability of the formation of an are at the gap H, during the passage of the currentthereacross, during the continuance of which, current may pass from the secondary 5, directly to and across the arc formation at the spark gap noted, without passing to the condenser F, to charge the same, which lat ter named action is necessary to the successful operation of the circuit, as will be understood.

It is to be understood that, in order to obtain high rates of discharge of current across the spark gap H, described above, two main essential conditions must be met and fulfilled, to wit, a small condenser, in shunt with the source of supply, must be used, so that it may be quickly filled and emptied, for

in the combination shown in Fig. 5, the

condenser is practically discharged, before it is agam charged, and secondly a short gap .must be employed in order that the poteninstead of a single gap as shown in Fig. 5;

In said Fig. 6, a condenser Gr, and a multiple spark gap H, in series with each other is included in the direct circuit between the secondary 5, the source of supply of the circuit shown,) and the primary 6, of the air core transformer to be energized.

It is to be understood that current supplied from the secondary 5, which current is alternating in character, operates on each wave flow, to pass through the condenser G, overcoming the dielectric resistance of the spark gap H, whereupon an arc will occur across said gap the current continuing to flow through the condenser G, by the polarization of the armatures, or poles of said condenser, such polarization due, it will be understood, to the character of the current supply, which as noted, is alternating.

From the foregoing described construction and operation of the circuits illustrated in Figs. 5 and G, which illustrate respectively, a condenser in shunt with its source of supply and in circuit with a spark gap, and a condenser incircuit with its source of supply andin series with a spark gap, it will be readily apparent that in each stance, the discharge of current across the gap, cannot be termed a true oscillatory dis-' charge, since in one of said instances, to wit, Fig. 5, such discharge is in part a spark discharge and in part an arc discharge, and in the other instance, Fig. 6, an arc discharge only. Further in neither of the circuits above referred to, can continuous high frequency oscillations be produced, for the reason that such oscillations are consequent upon the rapidity of the discharge of a condenser,in conjunctionwith a spark gap across which such discharge is made, in view of which, and of the further fact that in one of the instances noted, the condenser is fully dischargedduring which operation the oscillations noted occur,before it is again charged,during which operation, no 0scillations occur.

In view of the above recited facts the oscillatory circuit B, which forms a part of my invention, has been devised, and by reference to Fig. 1, wherein the circuit noted has been illustrated, it will be observed that such circuit consists essentially in the combination, in a single oscillatory circuit, of the operatve elements which are included in the circuits illustrated in Figs. 5 and 6, to which end I include a condenser F, similar to that shown in Fig. 5, with a circuit similar to that shown in Fig. 6, that is to say, having a condenser G, and a multiple spark gap H, in series with each other in the direct circuit between the secondary 5, which.

is the source of supply of the system, and the primary 6, of a transformer which is to b'e energized, and arranging the condenser :F, in shunt with said secondary 5, as shown in said Fig. 1. It is to be noted,'that in the combination above set forth, the condenser G, which is in series with the multiple gap, becomes a part of the true oscillating circuit B, and that such condenser undergoes a rapid reversal of polarity during the spark dis charge in the gap H. It is also to be noted that the condenser G, is of large capacity while the condenser F, which is in shunt with the secondary 5, is of small capacity,

as a matter of fact I have found by practice that a ratio of approximately 15 to 1, as

regards the capacities of the condensers noted, produce excellent results. I do not however desire to limit or confine myself to any particular ratio, as regards the comparative capacities of the condensers F and G, but may employ condensers having either a greater, or a less ratio than that noted. I have also found by practice that, whereas arcing in the gap H, of circuits similar to those set forth in Figs. 5 and 6, is liable to occur at any time, such arcing never occurs, or can occur, in circuits having their operating elements arranged as are those shown in Fig. 1, that is to say, having a condenser in shunt with the source of supply and a condenser in series with the spark gap, for at the moment of discharge the condenser which is in series with such gap, will, through the energy stored in the whole system, be undergoing rapid reversals of polarity, whereby polarization of such condenser, which will be understood, is necessary to establish an arc in the gap H,can-

not occur, but that instead thereof, a rapid succession of oscillatory discharges occur across the gap H, of said latter named cir cuits on every alternating wave flow.

Having thus set forth the arrangement of the several elements comprised in the oscillating circuit illustrated in Fig. 1, I will now proceed to first describe the manner in which such elements are charged and thereafter describe the manner in which the same are discharged. Assuming such charging to take place when the polarities of the secondary 5, are as illustrated in Fig. 1, that is to say, the opposite ends 0 and cl, of said secondary, respectively of positive polarity and of negative polarity, as indicated by the proper symbols thereon, then the opposite poles or armatures e and f, of the condenser F, will be charged from the secondary 5, by conduction and be respectively of the polarity indicated by the symbols thereon. Simultaneously with the charging of the condenser F, noted, the pole or armature g, of condenser G, will be charged by conduction from the positive pole 0, of secondary 5, as indicated by the symbol thereon. As will be understood, the positive charging of pole or armature g, of the condenser G, will operate to set up, or induce a, charge of opposite character in the remaining pole or armature h, of said condenser, as indicated by the negative symbol. It will also be understood that the several elements included in the multiple gap H, will each be charged by induction from the pole or armature nearest thereto upon the preceding element, thusthe pole z', of such gap H, will be charged by induction fromthe pole or armature h, of condenser G, and in like manner each succeeding element included in the gap H, will be charged by induction, the final element, 2'. e., the opposite pole j of said gap being charged partly by induction from the preceding element and partly by conduction from the negative end of the secondary 5, such charge in both instances, being of negative character. It is further to be understood that the pole e, of the shunt condenser F, and pole g, of the series condenser G, will when charged by conduction from the positive pole 0, of the secondary 5, as described, hold such charge as one unit of positive polarity, and in like manner the pole f, of said shunt condenser F, and pole i, of the spark gap H, will, at such time, hold as one unit, a charge of negative polarity, such being the polarity of the pole d, of said secondary 5, in view of which facts, it will be readily apparent that the oscillatory circuit B, will, when traced from pole j, through primary 6, of the air core transformer, show a true negative and positive series, thus, and f, negative,e and g, positive,h, negative,i, positive, and so on through the spark gap H, the several elements of which, are charged by induction only.

As has been hereinbefore described the oscillating circuit B, comprises elements which can only be charged by induction, to wit, the elements comprised between the pole or armature 'g, of the condenser G, and the pole j, of the multiple gap H, in view of which, it will be understood that said elements possess the ability to store induced energy in manner similar to small condensers arranged in series, as are the elements noted.

As a matter of factthe series gaps and ele-' ments forming them really operate as small serles condensers 1n connection wlth the V pole h, of condenser G, for while it is true that air is the dielectric for the condenser storage action of the multiple gap, it is also true that this same air permits a discharge of the energy so stored, when the potential difference necessary to such discharge has been attained.

Having thus described the manner in which the several operative elements comprised in the oscillating circuit B, are charged 1 will now describe the manner in which such elements are discharged, it being res membered that the shunt condenser F, is of I small capacity, and-purposely so, in order th'atit may be both charged and discharged quickly, and also that the series condenser Gr, 'is' of large capacity, in order that high discharge rates may be obtained for the production of continuous oscillations of high frequency. The manner of such discharge is as follows :Condenser F, when charged, can only discharge by way of condenser G and multiple gap H, when the potential of the induced charges in said condenser and-gap, are of suflicient strength to overcome the dielectric resistance of the air in the gap H, whichbecause of the fact that the air spaces in such gap are short, is not great, a discharge occurs, at which time the circuit B, will oscillate and the condensers F and G, included therein will act: through the gap H, upon the primary (3. I

As has been hereinbefore stated, one pole or armature of the condenser G, as well as the several elements comprised in the gap H, are charged by induction and, although the energy of such charge is small, because of the series condenser effect ,of the several elements referred to, the potential of the same may yet be raised suflieicntly to break down the dielectric resistance of the air in to occur, whereupon the stored energy of the elements noted, being small will be quickly dissipated and the potential necessary for discharge quickly lost, and .the discharge will end. It will thus be apparent that the dielectric resistance of the gap is not overcome after the first few oscillations during which the energy stored in the inductive elements noted is dissipated, and that therefore while there is a. more or less complete emptying of the energy stored in the inductive portion of the oscillator, there will be only a partial discharge in the conductive portion of such oscillator. that is to say, condensers F and pole or armature 7, of the condenser (lr. .lt will also be understood that since the condenser F, does not fully discharge, its potential will not drop to zero, but will. instead thereof, be quickly raised to its maximum strength, further, since the energy stored in the inductive portion of the oscillating crcuit is small as has been hereinbefore described, it will be quickly returned toits full strength when the discharge across the gaps has ceased, in view of which actions, it will be readily apparent that a rapd succession of dis charges across the gaps will occur, by which continuous high frequency oscillations will be set up in the primary 6, of the air core transformer I, for transference by induction to the secondary 8, of said. transformer.

It will be understood that a very great number of oscillations occur in the primary (3, of the air core transformer I, during the time period of each alternate current wave flow, such oscillations due to and caused by the discharges in the primary circuit, and that, since the current set up in the secondary 8, of said air core transformer I, is an induced current, that is to say, consequent upon the shocks, or impulses imparted to said secondary 8, by the oscillations which take place in the primary 6, such shocks, or impulses will result in setting up free oscillaiionS in said secondary, each of which oscillations in the secondary. will follow an oscillation in the primary. It will be understood, however, that the oscillations set up in the primary and secondary circuits noted, will not be of like character, for while each pulsation or oscillation set up in the primary circult, is of short duration and of what might be termed, rapidly decreasing oscillations, those set up in the secondary circuit by said primary circuit, are of longer duration and of what might be termed consecutive very slightly and gradually decreasing oscillations. a difference that is clearly illustrated in the diagrammatic view illustrated in l i g. 8.

In view of the foregoing described action of the inductive portion of oscillating circuit 13, which portion consists essentially of the pole h, of condenser G, and the several elements comprised in the multiple series spark gap H, it will be clearly apparent that dis charges occurring across such gap, are strongly damped, or quenched; that such action is consequent upon the damping, or quenching effect of the multiple series gap ll, in combination with the damping or quenching effect, due to the rapid loss of potential of the inductive portion; and that said rapid loss of potential of such inductive portion, is wholly due to the peculiar arrangement and combination of the elements Qull'lPl'l-SQCl in said inductive portion, with the remaining portion of the oscillatory circuit.

It is to be understood that the extent of the damping, or quenching effect produced by the inductive portion noted, depends wholly upon the comparative ratio between the shunt condenser H, and the series condenser G, whereby it may be inferred, that any desired ratio, of discharge, or group frequency. may be attained by the increase, or decrease of ratio between' the condensers noted.

As has been hereinbefore stated, the transmitting, or sonorous circuit C, includes the secondary 8, of air core transformer I, the antenna J and the interrupter J, the latter named consisting essentially in a rotatable disk 12, mounted upon a shaft 13, provided with a pulley to be turned by a belt 16, the disk is preferably made of non-conducting material and is provided with any desired number of contact making metallic pins 14,, which extend through the disk, to project at the sides thereof, and which are moved by the rotation of the disk through the gap 15, as shown, to rapidly interrupt current passing through circuit C.

From the foregoing description taken in connection with the drawings the operation of my invention will, it is thought, be understood, without a specific explanation, or further description to such end.

Having thus described my invention I claim and desire to secure by Letters Patent.

1. In a system for producing and transmitting continuous electrical oscillations of high frequency a source of electrical supply, a condenser of small capacity in shunt with such source of supply, a multiple spark gap, a condenser of large capacity in series with said multiple spark gap, and a transmitting circuit. 1

2. In a system for producing and transmitting continuous electrical oscillations of high frequency a source of electrical energy and a condenser of small capacity in shunt therewith, a multiple spark gap and a condenser of capacity exceeding twice the capacity of the shunt condenser in series with Said multiple spark gap, and a transmitting circuit.

3. An oscillatory circuit including the sec ondary of a step up transformer, a condenser of small capacity in shunt with said secondary, a multiple spark gap and a condenser of capacity exceeding twice the capacity of the shunt condenser, said larger condenser arranged in series with the multiple spark gap, the secondary of the step up transformer and the primary of an air core transformer also included in said oscillatory circuit, in combination with a transmitting circuit which includes the secondary of the air core transformer, and with an energy generating circuit which includes the primary of the step up transformer with which said small condenser is in shunt.

4. In a system for producing and transmitting continuous electrical oscillations of high frequency the combination of an oscillatory circuit including the secondary of a.

step up transformer, a condenser in shunt with said secondary and a condenser in series with said secondary and with a multiple spark gap which is also included in said oscillatory circuit, said series condenser having a capacity which exceeds the capacity of the shunt condenser by a ratio that would with a given supply current cause an arc to form in a single spark gap if such were to be substituted for the multiple gap, with a generating circuit including the primary of the step up transformer and a source of electrical supply, and with a transmitting circuit.

5. An oscillatory system, a generator of electricity in circuit with said oscillatory system, a plurality of condensers of unequal capacities included in said oscillatory system, a multiple spark gap comprising a plurality of independent conductive elements included in said oscillatory system in series with the condenser of largest capacity therein included, a transmitting system, and means to cause discharge of the condensers across said spark gap to actuate devices to continually energize said transmitting system.

6. An oscillatory system including in combination a multiple spark gap comprising a plurality of conductive elements having spaces therebetween, the secondary of a step up transformer to be energized to energize said oscillatory system, a condenser in shunt with said secondary, and means independent of the shunt condenser and of the spark gap to quench discharge of current across the spark gap before the shunt condenser .has been fully discharged.

7. In a system for producing and trans mitting continuous electrical oscillations of high frequency an oscillatory circuit including a multiple spark gap and a condenser of large capacity in series therewith, the secondary of a step up transformer and a condenser of small capacity in shunt'therewith, means to electrically energize the oscillatory circuit to charge said condensers, and means whereby discharge of current from said con-' densers across the spark gap is quenched before either of said condensers is fully discharged.

8. In a system for producing and transmitting continuous electrical oscillations of high frequency an oscillatory circuit including a multiple spark gap and a condenser of large capacity in series therewith, the secondary of a step up transformer and a condenser of small capacity in shunt therewith,

means for electrically energizing said oscil latory circuit to charge said condensers, and means for simultaneously varying rate of discharge of the condensers across the spark gap' and for quenching such discharge before the condensers have been fully discharged.

9. In a system for producing and trans mitting continuous electrical oscillations of high frequency an oscillatory circuit including the secondary of a stepup'transformer anda condenser of small capacity in shunt therewith a multiple spark gap and a condenser of large capacity in series therewith, means for electrically energizing said oscillatory circuit to charge condensers included therein, and means independent of the charging means to prevent the formation ofproduce continuous oscillations in the trans mitting system.

11. The method of producing electrical oscillations of high frequency which consists in electrically energizing an oscillatory circuit, charging the opposite poles of a condenser in shunt with the source of energy by conduction, simultaneously charging opposite poles of a condenser of large capacity arranged in series with a multiple spark gap included in said oscillatory circuitby conduction and induction, discharging said series condenser across the multiple spark gap, and controlling such condenser discharge at the gap.

12. The method of producing and transmitting electrical oscillations of high frequency which consists in passing a current of electricity throughan oscillatory circuit, charging a condenser of small capacity included in said oscillatory circuit in shunt with the source of energy, charging one pole only of each of a condenser of large capacity and a multiple spark gap included in said circuit and in series with each other and with the source of energy, charging the remainin poles of said condenser of large capacity an said spark gap by induction only, discharging said condensers across the multiple spark gap to excite oscillations in the oscillatory circuit, and controlling the discharge of said condensers at the spark gap.

In testimony whereof I hereto affix my signature in the presence of two witnesses.

DAVID e; McGAA.

Witnesses:

MARTIN E. MUSSER, ADAM BEITTEL. 

